Ultrasound diagnosis apparatus

ABSTRACT

The present invention relates to an ultrasound diagnosis apparatus ( 10 ), in particular for analyzing a fetus ( 62 ). An ultrasound data interface ( 66 ) is configured to receive 3D (three dimensional) ultrasound data from an object ( 12 ). The ultrasound diagnosis apparatus further comprises a measurement unit ( 70 ) for measuring anatomical structures of the object based on the segmentation data and a calculation unit ( 72 ) configured to calculate at least one biometric parameter based on the 3D ultrasound data.

FIELD OF THE INVENTION

The present invention relates to an ultrasound diagnosis apparatus, inparticular for analyzing a fetus. The present invention further relatesto an ultrasound diagnosis method, in particular for analyzing a fetus.The present invention further relates to an ultrasound imaging apparatusincluding a graphical user interface and an ultrasound diagnosisapparatus according to the present invention for displaying calculationresults of at least one calculated biometric parameter of the analyzedobject. The present finally relates to a computer program to carry outthe steps of the method according to the present invention.

BACKGROUND OF THE INVENTION

Ultrasound imaging systems are generally known for examination ofanatomical features in human patients. In particular, ultrasound imagingsystems and ultrasound diagnosis systems are used for prenatal screeningexamination of a fetus including measuring biometrics of the fetus ase.g. disclosed by US 2013/0173175 A1.

The fetal ultrasound is the modality of choice for fetus screening,diagnosis and the estimation of the gestational age. Current proceduresas disclosed by the above-mentioned document US 2013/0173175 A1 aremainly based on two dimensional ultrasound. However, ultrasound basedbiometric measurements are error prone and time-consuming and usuallylimited to the number of actually taken measurements. Assuming a normalcase, the gestational age can be estimated by just one measurement, e.g.the head circumference, the femur length of the like. For screening,biometrical measurements are typically individual performed for a giventask, e.g. the diameter of the cerebellum may be measured to detectbrain development abnormalities. These measurements however, lead tosituations where abnormalities are overlooked, or where the lack ofaccuracy of biometric measurements remains undetected.

Automated analysis of ultrasound images however enables the execution ofa large set of measurements in a short time. The images are readilyavailable in the system for further processing, while the ultrasoundmeasurements have to be inactively executed and entered into the system.The ability to perform automated biometric measurements the headincreases the efficiency of fetal screening. At the same time, it is notalways clear for the operator if the measurement can be trusted. Due tothe redundancy contained in a larger set of measurements it is possibleto detect disagreement based on a certain deviation threshold that e.g.relates to typical modality dependent measurement accuracy. In case of adisagreement at this stage, it is unclear if it is caused by ameasurement error or by an abnormality. The operator is guided tooutsell this question by a display of a disagreeing measurement on topof the image showing the related anatomical structure.

However, the ultrasound diagnosis systems available do not have an errordetection system which indicates to the operator whether abnormalitiesof the detected biometric parameter is correct if it deviates fromexpected biometric parameter.

US 2007/0081705 A1 discloses a method for segmenting and measuringanatomical structures in fetal ultrasound images including the steps ofproviding a digitized ultrasound image of a fetus comprising a pluralityof intensities corresponding to a domain of points on a 3D grid,providing a plurality of classifiers trained to detect anatomicalstructures in said image of said fetus, and segmenting and measuring ananatomical structure using said image classifiers by applying saidelliptical contour classifiers to said fetal ultrasound image, wherein aplurality of 2D contours characterizing said anatomical structure aredetected. The anatomical structure measurement can be combined withmeasurement of another anatomical structure to estimate gestational ageof the fetus.

EP 2 624 211 A1 discloses an image processing apparatus including: adata acquisition device for acquiring image data of a subject includinga target bone; and a data processor for acquiring binary image data byperforming thresholding based on the image data, segmenting the binaryimage data into a plurality of segments by labeling, determining one ofthe plurality of segments as a target image based on imagecharacteristics of the target bone, and measuring a length of the targetbone based on the target image.

EP 2 982 306 A1 discloses an ultrasound diagnosis apparatus including: adata acquisition unit configured to acquire volume data for a head of anobject; an image processor configured to detect a mid-sagittal plane(MSP) from the volume data, generate an MSP image corresponding to theMSP, detect at least one measurement plane based on the MSP, andgenerate at least one measurement plane image corresponding to the atleast one measurement plane; and a display configured to display the MSPimage and the at least one measurement plane image on a single screen.

SUMMARY OF THE INVENTION

It is an object of the present invention to provide an improvedultrasound diagnosis apparatus, which comprises an automated errordetection for calculated and measured biometric parameters, and whichprovides an improved accuracy of the provided ultrasound detection. Itis a further object of the present invention to provide a correspondingmethod, a corresponding ultrasound imaging apparatus and a correspondingcomputer program for implementing such a method.

In a first aspect of the present invention, an ultrasound diagnosisapparatus, in particular for analyzing an object is presented,comprising:

an ultrasound data interface configured to receive 3D (threedimensional) ultrasound data from the object,

a plane extraction unit configured to provide 2D ultrasound planes basedon the 3D ultrasound data,

a segmentation unit for segmenting anatomical structures of the objectin the 2D ultrasound planes and for providing segmentation data of theanatomical structures;

a measurement unit for measuring the anatomical structures of the objectbased on the segmentation data of the anatomical structures, and

a calculation unit configured to calculate at least one biometricparameter based on the measured anatomical structures of the object.

In a further aspect of the present invention an ultrasound diagnosismethod, in particular for analyzing an object is presented, comprisingthe steps of:

receiving 3D (three dimensional) ultrasound data at an ultrasound datainterface from the object,

extracting 2D ultrasound planes based on the 3D ultrasound data;

segmenting anatomical structures of the object in the 2D ultrasoundplanes to provide segmentation data of the anatomical structures;

measuring anatomical structures of the object based on the segmentationdata of the anatomical structures, and

calculating at least one biometric parameter based on the measuredanatomical structures of the object.

In a further aspect of the present invention, an ultrasound imagingapparatus, in particular for imaging an object, is presented,comprising:

a graphical user interface, in particular a display unit configured todisplay ultrasound image data, and

an ultrasound diagnosis apparatus as claimed in claim 1 for analyzingthe object, wherein the graphical user interface is adapted to displaythe calculation results of the at least one biometric parameter.

In a still further aspect of the present invention, a computer ispresented comprising program code means for causing a computer to carryout to the steps of the above-mentioned method when said computerprogram is carried out on a computer.

Preferred embodiments of the invention are defined in the dependentclaims. It shall be understood that the claim method has similar and/oridentical preferred embodiments as the claimed device and as defined inthe dependent claims.

The present invention is based on the idea to utilize three dimensionalultrasound data captured from the object and to provide automaticallyextracted two dimensional data planes in order to determine biometricparameters for measuring certain biometric components of the object, inparticular the gestational age of the fetus. Due to the measurement ofthe object by three dimensional (3D) ultrasound systems, the exposure ofthe irradiation in particular of the fetus is reduced so that the healthof the object is not affected compared to CT image based 3D data.Consequently, the ultrasound diagnosis apparatus can be utilized todetermine critical biometric 3D parameters while the health of theobject is not affected by the ultrasound radiation.

In a preferred embodiment, the ultrasound diagnosis apparatus furthercomprises a data interface configured to receive biometric data forcalculating the at least one biometric parameter. This is a possibilityto provide reference data to compare the calculated biometric parameterwith prior calculated parameters or with biometric parameters of theliterature so that the technical effort for determining a wrongbiometric parameter is reduced.

The ultrasound diagnosis apparatus further comprises a segmentation unitfor segmenting anatomical structures of the object in the ultrasounddata and for providing segmentation data of the anatomical structures,wherein the measurement unit is provided for measuring anatomicalstructures of the object based on the segmentation data if this isrequired by the sub-sequent measurement unit, if not the segmentationunit can be omitted. The segmentation unit gives a possibility ofimproving the measurement results of the anatomical structures and thedetermination of the at least one biometric parameter.

In a further preferred embodiment, the biometric data comprisespredefined model-based segmentation data. This is a possibility toreduce the technical effort for determining an error of the biometricparameter based on the segmentation data, since the biometric parameteris based on model-based segmentation data.

The ultrasound diagnosis apparatus further comprises a plane extractionunit configured to provide 2D (two dimensional) ultrasound planes basedon the 3D ultrasound data, wherein the segmentation unit is configuredto segment the anatomical structures based on the 2D ultrasound planes.This is a possibility to reduce the technical effort, since thesegmentation of the anatomical structures based on the 2D ultrasoundplanes can be technically less complex than the segmentation of 3Dvolume image data.

In a further preferred embodiment, the measurement unit is configured tomeasure the at least one biometric parameter based on a directmeasurement (without an explicit prior segmentation), e.g. using machinelearning methods such as neural network based approaches. This

In a further preferred embodiment, the measurement unit is configured tomeasure the at least one biometric parameter based on a measurementalgorithm. This is a possibility to further reduce the complexity of thecalculation of the biometric parameter.

It is further preferred, if the algorithm is preselected and stored in amemory of the ultrasound diagnosis apparatus. This is a possibility toutilize a predefined algorithm by default in order to provide a firstestimation of the biometric parameter which utilize the system inaddition of flexibility and a simplicity for the operator to handle theapparatus.

In a further preferred embodiment, the measurement algorithm ispreselected by the user. This is a possibility to further simplify theultrasound diagnosis apparatus and the calculated biometric parameter,since the user is familiar with the measurement algorithm of the atleast one biometric parameter.

In a further preferred embodiment, the measurement algorithm is selectedbased on the calculated at least one biometric parameter. This is apossibility to iteratively improve the calculation of the at least onebiometric parameter.

In a further preferred embodiment, the measurement unit is configured tomeasure the anatomical structures based on different measurementalgorithms. This is a possibility to automatically adapt the measurementalgorithm and to iteratively reach an optimal measurement algorithm todetermine the current biometric parameter.

In a further preferred embodiment, the measurement unit is configured tomeasure the anatomical structures based on different measurementalgorithms. This is a possibility to compare the measurement results ofthe different measurement algorithms in order to find the bestmeasurement algorithm to determine the biometric parameter to becalculated.

In a further preferred embodiment, the measurement unit is configured tomeasure the 3D image data based on different anatomical structures ofthe object. This is a possibility to correlate a set of measurements ofdifferent measurements of e.g. a left and a right anatomical featuree.g. of the left and the right thighbone (femur). This is a furtherpossibility to provide a biometry accuracy estimation based on a set ofultrasound measurements.

In a further preferred embodiment, the calculation unit is configured tocalculate a cross correlation of the segmentation data based ondifferent ultrasound data in order to determine errors in measurementsfrom the given 3D ultrasound data. This is a possibility to determineerrors in the measured ultrasound data with low technical effort, sincedifferent ultrasound data is utilized to compare the biometric parameterand to calculate a cross correlation.

In a further preferred embodiment, the calculation unit is configured tocalculate a cross correlation of the segmentation data based ondifferent measurement algorithms in order to determine deviation in the3D ultrasound data. This is a possibility to determine erroneousultrasound data with low technical effort, since the cross correlationof the different measurement algorithms can be compared with lowtechnical effort.

In a further preferred embodiment, the measurement unit is configured todetermine errors based on a cross correlation of different algorithms.

In a further preferred embodiment, the ultrasound diagnosis apparatusfurther comprises a graphical user interface, in particular a displayunit, e.g. a touchscreen which is configured to display the calculationresults of the at least one biometric parameter and which can beutilized as input unit to input instructions of the user. This is apossibility to present the measured and calculated biometric parameterto the user and a possible error of the calculated parameter so that thehandling effort of the ultrasound diagnosis apparatus can be reduced.

In a further embodiment, the measurement unit is configured to perform aplurality of different biometric measurements of the anatomicalstructures of the object based on the segmentation data of theanatomical structures, and wherein the calculation unit is configured tocalculate a parameter value of the at least one biometric parameterbased on each of the plurality of different biometric measurements,separately.

In a further embodiment, each of the plurality of different biometricmeasurements performed by the measurement unit (i) evaluates a differentbiometric measure of the object, (ii) is performed based on a differentmeasurement algorithm, and/or (iii) is performed based on segmentationdata derived from a different 3D ultrasound data set.

In a further embodiment, the calculation unit is configured to calculatea cross-correlation of the parameter values calculated based on each ofthe plurality of different biometric measurements.

In a further embodiment, the calculation unit is configured to estimatean accuracy of the calculation of the at least one biometric parameterif the calculated cross-correlation is above a predefined correlationthreshold.

In a further embodiment, the calculation unit is configured to calculatea further parameter value of the at least one biometric parameter basedon a further biometric measurement performed by the measurement unit ifthe calculated cross-correlation is below a predefined correlationthreshold.

In a further embodiment, the calculation unit is configured to comparethe further parameter value with the parameter values calculated basedon each of the plurality of different biometric measurements and toderive a confidence value based on said comparison.

As mentioned above, the three dimensional ultrasound data can improvethe accuracy of the measurements of the object in order to improve thecalculation results of the at least one biometric parameter to improvethe diagnosis of the ultrasound diagnosis apparatus in general. Further,due to the ultrasound image data taken from the object, the radiationexposure of the object can be reduced, so that the stress for the objectcan be reduced.

Further, due to different calculation algorithms and different databases, the technical effort to determine an error in the capturedultrasound data can be reduced.

BRIEF DESCRIPTION OF THE DRAWINGS

These and other aspects of the invention will be apparent from andelucidated with reference to the embodiment(s) described hereinafter. Inthe following drawings

FIG. 1 shows a schematic representation of an ultrasound imaging systemin use to scan a part of a patient's body;

FIG. 2 shows a schematic block diagram of an embodiment of an ultrasoundimaging system with an array transducer;

FIG. 3 shows a schematic diagram of the ultrasound imaging apparatus forscanning a fetus;

FIG. 4 shows a schematic diagram of the patient to be scanned in twodifferent viewing directions; and

FIG. 5 shows a schematic flow diagram of the ultrasound diagnosis methodfor analyzing the fetus.

DETAILED DESCRIPTION OF THE INVENTION

Before referring to the medical ultrasound diagnosis apparatus 10according to an aspect of the present invention, the basic principles ofan ultrasound system 100 shall be explained with reference to FIGS. 1and 2.

FIG. 1 shows a schematic illustration of an ultrasound system 100, inparticular a medical three-dimensional (3D) ultrasound imaging system.The ultrasound imaging system 100 is applied to inspect a volume of ananatomical site, in particular an anatomical site of a patient 12 overtime. The ultrasound system 100 comprises an ultrasound probe 14 havingat least one transducer array having a multitude of transducer elementsfor transmitting and/or receiving ultrasound waves. In one example, eachof the transducer elements can transmit ultrasound waves in form of atleast one transmit impulse of a specific pulse duration, in particular aplurality of subsequent transmit pulses. The transducer elements arepreferably arranged in a two-dimensional array, in particular forproviding a multi-planar or three-dimensional image.

A particular example for a three-dimensional ultrasound system which maybe the CX40 Compact Xtreme ultrasound system sold by the applicant, inparticular together with a X6-1 or X7-2t TEE transducer of the applicantor another transducer using the xMatrix technology of the applicant. Ingeneral, matrix transducer systems as found on Philips iE33 systems ormechanical 3D/4D transducer technology as found, for example, on thePhilips iU22 and HD15 systems may be applied in conjunction with thecurrent invention.

A 3D ultrasound scan typically involves emitting ultrasound waves thatilluminate a particular volume within a body, which may be designated astarget volume or volumetric region. This can be achieved by emittingultrasound waves at multiple different angles. A set of volume data isthen obtained by receiving and processing reflected waves. The set ofvolume data is a representation of the target volume within the bodyover time. Since time is usually denoted as fourth dimension, suchultrasound system 100 delivering a 3D image sequence over time, issometimes also referred to a 4D ultrasound imaging system.

It shall be understood that the ultrasound probe 14 may either be usedin a non-invasive manner (as shown in FIG. 1) or in an invasive manneras this is usually done in TEE (not explicitly shown). The ultrasoundprobe 14 may be hand-held by the user of the system, for example medicalstaff or a physician. The ultrasound probe 14 is applied to the body ofthe patient 12 so that an image of an anatomical site, in particular ananatomical object of the patient 12 is provided.

Further, the ultrasound system 100 may comprise an image reconstructionunit 16 that controls the provision of a 3D image sequence via theultrasound system 100. As will be explained in further detail below, theimage reconstruction unit 16 may control not only the acquisition ofdata via the transducer array of the ultrasound probe 14, but alsosignal and image processing that form the 3D image sequence out of theechoes of the ultrasound beams received by the transducer array of theultrasound probe 14.

The ultrasound system 100 may further comprise a display 18 fordisplaying the 3D image sequence to the user. Still further, an inputdevice 20 may be provided that may comprise keys or a keyboard 22 andfurther inputting devices, for example a trackball 24. The input device20 might be connected to the display 18 or directly to the imagereconstruction unit 16.

FIG. 2 illustrates a schematic block diagram of the ultrasound system100. The ultrasound probe 14 may, for example, comprise a CMUTtransducer array 26. The transducer array 26 may alternatively comprisepiezoelectric transducer elements formed of materials such as PZT orPVDF. The transducer array 26 is a one- or a two-dimensional array oftransducer elements capable of scanning in three dimensions for 3Dimaging. The transducer array 26 is coupled to a microbeamformer 28 inthe probe which controls transmission and reception of signals by theCMUT array cells or piezoelectric elements. Microbeamformers are capableof at least partial beamforming of the signals received by groups or“patches” of transducer elements as described in U.S. Pat. No. 5,997,479(Savord et al.), U.S. Pat. No. 6,013,032 (Savord), and U.S. Pat. No.6,623,432 (Powers et al.) The microbeamformer 28 may be coupled by aprobe cable to a transmit/receive (T/R) switch 30 which switches betweentransmission and reception and protects the main beamformer 34 from highenergy transmit signals when a microbeamformer 28 is not used and thetransducer array 26 is operated directly by the main beamformer 34. Thetransmission of ultrasonic beams from the transducer array 26 undercontrol of the microbeamformer 28 is directed by a transducer controller32 coupled to the microbeamformer 28 by the T/R switch 30 and the mainsystem beamformer 34, which receives input from the user's operation ofthe user interface or control panel 22. One of the functions controlledby the transducer controller 32 is the direction in which beams aresteered and focused. Beams may be steered straight ahead from(orthogonal to) the transducer array 26, or at different angles for awider field of view. The transducer controller 32 can be coupled tocontrol a DC bias control 58 for the CMUT array. The DC bias control 58sets DC bias voltage(s) that are applied to the CMUT cells.

The partially beamformed signals produced by the microbeamformer 26 onreceive are coupled to the main beamformer 34 where partially beamformedsignals from individual patches of transducer elements are combined intoa fully beamformed signal. For example, the main beamformer 34 may have128 channels, each of which receives a partially beamformed signal froma patch of dozens or hundreds of CMUT transducer cells or piezoelectricelements. In this way the signals received by thousands of transducerelements of the transducer array 26 can contribute efficiently to asingle beamformed signal.

The beamformed signals are coupled to a signal processor 36. The signalprocessor 36 can process the received echo signals in various ways, suchas bandpass filtering, decimation, I and Q component separation, andharmonic signal separation which acts to separate linear and nonlinearsignals so as to enable the identification of nonlinear (higherharmonics of the fundamental frequency) echo signals returned fromtissue and/or microbubbles comprised in a contrast agent that has beenpre-administered to the body of the patient 12. The signal processor 36may also perform additional signal enhancement such as specklereduction, signal compounding, and noise elimination. The bandpassfilter in the signal processor 36 can be a tracking filter, with itspassband sliding from a higher frequency band to a lower frequency bandas echo signals are received from increasing depths, thereby rejectingthe noise at higher frequencies from greater depths where thesefrequencies are devoid of anatomical information.

The processed signals may be transferred to a B mode processor 38 and aDoppler processor 40. The B mode processor 38 employs detection of anamplitude of the received ultrasound signal for the imaging ofstructures in the body such as the tissue of organs and vessels in thebody. B mode images of structure of the body may be formed in either theharmonic image mode or the fundamental image mode or a combination ofboth as described in U.S. Pat. No. 6,283,919 (Roundhill et al.) and U.S.Pat. No. 6,458,083 (Jago et al.)

The Doppler processor 40 may process temporally distinct signals fromtissue movement and blood flow for the detection of the motion ofsubstances such as the flow of blood cells in the image field. TheDoppler processor 40 typically includes a wall filter with parameterswhich may be set to pass and/or reject echoes returned from selectedtypes of materials in the body. For instance, the wall filter can be setto have a passband characteristic which passes signal of relatively lowamplitude from higher velocity materials while rejecting relativelystrong signals from lower or zero velocity material. This passbandcharacteristic will pass signals from flowing blood while rejectingsignals from nearby stationary or slowing moving objects such as thewall of the heart. An inverse characteristic would pass signals frommoving tissue of the heart while rejecting blood flow signals for whatis referred to as tissue Doppler imaging, detecting and depicting themotion of tissue. The Doppler processor 40 may receive and process asequence of temporally discrete echo signals from different points in animage field, the sequence of echoes from a particular point referred toas an ensemble. An ensemble of echoes received in rapid succession overa relatively short interval can be used to estimate the Doppler shiftfrequency of flowing blood, with the correspondence of the Dopplerfrequency to velocity indicating the blood flow velocity. An ensemble ofechoes received over a longer period of time is used to estimate thevelocity of slower flowing blood or slowly moving tissue.

The structural and motion signals produced by the B mode and Dopplerprocessors 38, 40 may then be transferred to a scan converter 44 and amultiplanar reformatter 54. The scan converter 44 arranges the echosignals in the spatial relationship from which they were received in adesired image format. For instance, the scan converter 44 may arrangethe echo signal into a two dimensional (2D) sector-shaped format, or apyramidal three dimensional (3D) image. The scan converter 44 canoverlay a B mode structural image with colors corresponding to motion atpoints in the image field with their Doppler-estimated velocities toproduce a color Doppler image which depicts the motion of tissue andblood flow in the image field. The multiplanar reformatter 54 willconvert echoes which are received from points in a common plane in avolumetric region of the body into an ultrasonic image of that plane, asdescribed in U.S. Pat. No. 6,443,896 (Detmer). A volume renderer 52converts the echo signals of a 3D data set into a projected 3D imagesequence 56 over time as viewed from a given reference point asdescribed in U.S. Pat. No. 6,530,885 (Entrekin et al.). The 3D imagesequence 56 is transferred from the scan converter 44, multiplanarreformatter 54, and volume renderer 52 to an image processor 42 forfurther enhancement, buffering and temporary storage for display on thedisplay 18. In addition to being used for imaging, the blood flow valuesproduced by the Doppler processor 40 and tissue structure informationproduced by the B mode processor 38 may be transferred to aquantification processor 46. This quantification processor 46 mayproduce measures of different flow conditions such as the volume rate ofblood flow as well as structural measurements such as the sizes oforgans and gestational age. The quantification processor 46 may receiveinput from the user control panel 22, such as the point in the anatomyof an image where a measurement is to be made. Output data from thequantification processor 46 may be transferred to a graphics processor50 for the reproduction of measurement graphics and values with theimage on the display 18. The graphics processor 50 can also generategraphic overlays for display with the ultrasound images. These graphicoverlays can contain standard identifying information such as patientname, date and time of the image, imaging parameters, and the like. Forthese purposes the graphics processor 50 may receive input from the userinterface 22, such as patient name. The user interface 22 may be coupledto the transmit controller 32 to control the generation of ultrasoundsignals from the transducer array 26 and hence the images produced bythe transducer array and the ultrasound system. The user interface 22may also be coupled to the multiplanar reformatter 54 for selection andcontrol of the planes of multiple multiplanar reformatted (MPR) imageswhich may be used to perform quantified measures in the image field ofthe MPR images.

Again, it shall be noted that the aforementioned ultrasound system 100has only been explained as one possible example for an application ofthe medical ultrasound image processing device 10. It shall be notedthat the aforementioned ultrasound system 100 does not have to compriseall of the components explained before. On the other hand, theultrasound system 100 may also comprise further components, ifnecessary. Still further, it shall be noted that a plurality of theaforementioned components do not necessarily have to be realized ashardware, but may also be realized as software components. A pluralityof the aforementioned components may also be comprised in commonentities or even in one single entity and do not all have to be realizedas separate entities, as this is schematically shown in FIG. 2.

FIG. 3 shows a schematic view of the ultrasound diagnosis apparatuswhich is generally denoted by 10. The ultrasound diagnosis apparatus 10scans by means of the ultrasound probe 14 a fetus, which is generallydenoted by 62. The ultrasound probe 14 scans an anatomical site, whichforms a region of interest and which is generally denoted by 64. Theultrasound probe 14 is connected to the image reconstruction unit 16 viaan ultrasound data interface 66 and which comprises a segmentation unit68, a measurement unit 70 and a calculation unit 72.

The image reconstruction unit 16 is connected to the display 18 fordisplaying the results of the ultrasound scan and which is connected tothe input device 20 for inputting instructions to control the medicalultrasound diagnosis apparatus 10.

The segmentation unit 68 is provided for segmenting anatomicalstructures of the fetus 62 in the 3D ultrasound data captured by theultrasound probe 14 and the segmentation unit 68 provides segmentationdata of the anatomical structures of the fetus 62. The measurement unit72 is provided for measuring the anatomical structures of the fetus 62based on the segmentation data provided by the segmentation unit 68. Thecalculation unit 72 is configured to calculate at least one biometricparameter of the fetus 62 based on the segmentation data provided by thesegmentation unit 68. Based on the so-determined at least one biometricparameter, different biometric analyses can be performed, in particularthe gestational age of the fetus 62 can be calculated based on measuredsizes of anatomical structures in the head of the fetus 62.

FIG. 4 shows a detailed schematic diagram of the object 12 to be scannedby the ultrasound probe 14, wherein in this particular case the objectis a fetus 62 to be scanned and to determine a gestational age based onbiometric sizes of different individual biometrical parameter within thehead of the fetus 62.

In order to measure the biometric parameter, at first a plurality ofultrasound scans are performed at different positions with differentregions of interest 64, 64′, as shown in FIG. 4 and the scans areprovided via the ultrasound data interface 66 to the segmentation unit68 in order to perform a model-based segmentation followed by amodel-based measurement.

In the particular case shown in FIG. 4, a calculation of the gestationalage is performed on all different individual biometric measurements,wherein a direct trust correlation of the individual measurements isperformed in order to evaluate an agreement between the measurements ofthe different model-based segmentation measurements. In case of anagreement between the different individual measurements, the accuracy isestimated of the gestational age and all other measurements.

In the case of a disagreement or a miscorrelation between the individualmeasurements, the measurement unit 72 runs different mathematicalgorithms in order to extract the at least one biometric parameter ofthe different viewing directions and the different biometricmeasurements captured by the ultrasound probe 14. The measurement unit72 evaluates similarities between the different biometric measurementsand derives a confidence measure based on the different viewingdirections 64, 64′.

This is a possibility to rule out measurement errors, to correct errorsor to exclude individual measurements in order to achieve correctcalculation of the biometric parameter and to achieve a correctcalculation of the gestational age of the fetus 62.

If the disagreement between the measurements is persistent, themeasurement unit 72 checks the ultrasound data for related abnormalitiesand guides the operator to assess the respective relevant anatomicalstructures.

To evaluate the ultrasound measurements, the model-based segmentationand the calculated at least one biometric parameter on the basis of acomparison to prior captured ultrasound images of the same fetus 62 orin comparison to biometric parameters of a different fetus stored e.g.in the memory 60 or in a database can be performed.

FIG. 5 shows a schematic flow diagram of the ultrasound diagnosis methodaccording to the present invention, which is generally denoted by 200.

At first a plurality of ultrasound measurement of a different region ofinterests 64, 64′ are performed at step 202 At step 204, the calculationunit 72 calculates a correction analysis of the calculated biometricparameter, which is in this case the gestational age via a pairwisecorrelation. If any agreement between the different biometric parametersof the different viewing directions 64, 64′ is achieved, at step 206 abiometric accuracy estimation is performed.

If no agreement can be achieved between the different biometricparameters of the different viewing directions 64, 64′ is present, avisual feedback of the conflict measurement can be provided to the uservia the display 18 at step 208.

Based on the visual feedback provided in step 208, an assessment of therelated abnormalities is performed by the user at step 210 about theamount of disagreement, wherein the crucia anatomy is displayed on thedisplay screen 18.

If an error of the measurement can be detected at step 208, therespective measurement is excluded or the conflict measurement iscorrected at step 212. Based on the so-corrected measurement, thebiometric accuracy estimation can be performed at step 206.

The biometric accuracy estimation is calculated by the measurement unit72 via one or a plurality of measurements or calculation algorithms. Themeasurement algorithm is either preselected by the system itself or bythe user and utilized for a first estimation of the biometric parameter.In case of a disagreement of the gestational age, the measurement unit72 measures the anatomical structures based on different measuredalgorithms selected by the system itself in order to stepwise achieve apairwise correlation of the analysis.

The present ultrasound diagnosis apparatus 10 may utilize 3D fetalmodels in order to determine the anatomical structures of the object 12and may utilize the measured 3D ultrasound data received from theultrasound probe 14 directly or may comprise a plane extraction unitwithin the image reconstruction unit 16, which is configured to provide2D ultrasound planes based on the 3D ultrasound data so that thesegmentation effort is in general reduced.

While the invention has been illustrated and described in detail in thedrawings and foregoing description, such illustration and descriptionare to be considered illustrative or exemplary and not restrictive; theinvention is not limited to the disclosed embodiments. Other variationsto the disclosed embodiments can be understood and effected by thoseskilled in the art in practicing the claimed invention, from a study ofthe drawings, the disclosure, and the appended claims.

In the claims, the word “comprising” does not exclude other elements orsteps, and the indefinite article “a” or “an” does not exclude aplurality. A single element or other unit may fulfill the functions ofseveral items recited in the claims. The mere fact that certain measuresare recited in mutually different dependent claims does not indicatethat a combination of these measures cannot be used to advantage.

A computer program may be stored/distributed on a suitable medium, suchas an optical storage medium or a solid-state medium supplied togetherwith or as part of other hardware, but may also be distributed in otherforms, such as via the Internet or other wired or wirelesstelecommunication systems.

Any reference signs in the claims should not be construed as limitingthe scope.

1. Ultrasound diagnosis apparatus, in particular for analyzing anobject, comprising: an ultrasound data interface configured to receive3D ultrasound data from the object, a plane extraction unit configuredto provide 2D ultrasound planes based on the 3D ultrasound data, asegmentation unit for segmenting anatomical structures of the object inthe 2D ultrasound planes and for providing segmentation data of theanatomical structures; a measurement unit for measuring the anatomicalstructures of the object based on the segmentation data of theanatomical structures, and a calculation unit configured to calculate atleast one biometric parameter based on the measured anatomicalstructures of the object.
 2. Ultrasound diagnosis apparatus as claimedin claim 1, further comprising a data interface configured to receivebiometric data for calculating the at least one biometric parameter. 3.Ultrasound diagnosis apparatus as claimed in claim 2, wherein thebiometric data comprises predefined model-based segmentation data. 4.Ultrasound diagnosis apparatus as claimed in claim 1, wherein themeasurement unit is configured to calculate the at least one biometricparameter based on a measurement algorithm.
 5. Ultrasound diagnosisapparatus as claimed in claim 4, wherein the algorithm is preselectedand stored in a memory of the ultrasound diagnosis apparatus. 6.Ultrasound diagnosis apparatus as claimed in claim 5, wherein themeasurement algorithm is preselected by the user.
 7. Ultrasounddiagnosis apparatus as claimed in claim 4, wherein the measurementalgorithm is selected based on the calculated at least one biometricparameter.
 8. Ultrasound diagnosis apparatus as claimed in claim 1,wherein the measurement unit is configured to perform a plurality ofdifferent biometric measurements of the anatomical structures of theobject based on the segmentation data of the anatomical structures, andwherein the calculation unit is configured to calculate a parametervalue of the at least one biometric parameter based on each of theplurality of different biometric measurements, separately.
 9. Ultrasounddiagnosis apparatus as claimed in claim 8, wherein the plurality ofdifferent biometric measurements performed by the measurement unit (i)evaluate different biometric measures of the object, (ii) are performedbased on different measurement algorithms, and/or (iii) are performedbased on segmentation data derived from different 3D ultrasound datasets.
 10. Ultrasound diagnosis apparatus as claimed in claim 8, whereinthe calculation unit is configured to calculate a cross-correlation ofthe parameter values calculated based on each of the plurality ofdifferent biometric measurements.
 11. Ultrasound diagnosis apparatus asclaimed in claim 10, wherein the calculation unit is configured toestimate an accuracy of the calculation of the at least one biometricparameter if the calculated cross-correlation is above a predefinedcorrelation threshold.
 12. Ultrasound diagnosis apparatus as claimed inclaim 10, wherein the calculation unit is configured to calculate afurther parameter value of the at least one biometric parameter based ona further biometric measurement performed by the measurement unit if thecalculated cross-correlation is below a predefined correlationthreshold.
 13. Ultrasound diagnosis apparatus as claimed in claim 12,wherein the calculation unit is configured to compare the furtherparameter value with the parameter values calculated based on each ofthe plurality of different biometric measurements and to derive aconfidence value based on said comparison.
 14. Ultrasound diagnosismethod, in particular for analyzing an object, comprising the steps of:receiving 3D ultrasound data at an ultrasound data interface from theobject, extracting 2D ultrasound planes based on the 3D ultrasound data;segmenting anatomical structures of the object in the 2D ultrasoundplanes to provide segmentation data of the anatomical structures;measuring the anatomical structures of the object based on thesegmentation data of the anatomical structures, and calculating at leastone biometric parameter based on the measured anatomical structures ofthe object.
 15. Ultrasound imaging apparatus, in particular for imagingan object, comprising: a graphical user interface, in particular adisplay unit configured to display ultrasound image data, and anultrasound diagnosis apparatus as claimed in claim 1 for analyzing theobject, wherein the graphical user interface is adapted to display thecalculation results of the at least one biometric parameter.